I'm of on holiday soon and am really looking forward to going a bit mad with the camera. I've had a UV filter on my main lnses (17-85 and 10-22 canon) since new mainly for protection but have been reading on these forums about polarizing filters being particually good for scenes with water in them. Now i'm not going to be shooting anything specific but it's a cruise so all the locations i'm going to will be on the coast and, therefore have a lot of water and (hopefully) bright sunshine in them.

Baring in mind I don't want to be changing filters every 5 seconds should I stick with the UV and just deal with the light or would a polarizing filter be benificial and give the shots some extra edge?

It sounds as though a polarising filter on your 17-85 lens would give you some useful extra options and don't forget that it can affect the sky as well as water. I you decide to get one then do so some weeks before your holiday so you can get some practice tuning the angle of polarisation to get the effect you want. And it's only the work of a few moments to remove it when it isn't needed.